Pyrethrum pesticide synergized with lower alkyl aryl ketone



United States Patent PYRETHRUM PESTICIDE SYNERGIZED WITH LOWER ALKYL ARYL KETONE George Stuart Shillitoe, London, and Arthur Douglas Harford, Sunbury-on-Thames, England, assignors to The British Petroleum Company Limited, London, England, a joint-stock corporation of England No Drawing. Application June 10, 1955, Serial No. 514,782

Claims priority, application Great Britain June 15, 1954 9 Claims. (Cl. 167-24) This invention'relates to improved pest combating compositions.

It is known to use compositions comprising pyrethrins for combating pests. Usually the pyrethrins are employed in the form of an extract of the active principle of a plant of the genus Pyrethrum and conveniently may be applied, as solutions in petroleum distillate fractions, in the form of liquid sprays.

While it is recognised that the pyrethrins have a degree of toxicity for many insect pests, they are of particular value in providing the means of rapidly immobilising the pests and it is common practice to include in the pyrethrin containing composition at least one other component which although slower acting is of higher toxicity. By the use of such compositions it is possible to ensure that the pests are rapidly immobilised until the slower acting component has had time to be effective. Thus, in the application of insecticidal containing sprays to the killing of house flies it is considered desirable to include in the composition a component such as pyrethrin which provides a high knock down rate.

Pyrethrins and extracts containing pyrethrins are expensive and it is therefore desirable to reduce as far as possible the quantities of these materials employed in the compositions.

It has been shown that the addition of certain compounds, which are not necessarily insecticidal, to these compositions leads to an increase in the efficiency of the compositions and thus, by their inclusion, permits a reduction in the amount of pyrethrins employed.

A compound, which in admixture with another component gives a composition having a toxicity greater than equivalent amounts of the compound or the component when used alone, is known as a synergist.

Examples of synergists which have been used in sprays for combating house-flies are iso-butyl undecylenarnide and sesame oil. Among the compounds which have been tried and found to lack synergistic products is included chalcone (alpha-benzalacetophenone) Usually the compositions containing pyrethrins are employed in the form of sprays and the technical literature contains a description of a wide variety of solvents which may be employed for producing a solution of suitable characteristics for application in this manner. Thus a number of compositions are described containing petroleum fractions together with an oxygenated solvent, such as ketones. Thus compositions have been described containing an extract of pyrethin in kerosene or a heavy petroleum oil together with a phenol and as solvent a cyclic ketone such as cyclohexanone.

It has now been found that in addition to their properties as solvents, aryl alkyl ketones have the unexpected property of acting as a synergist for pyrethrins.

It is an object of the present invention. to provide improved pest-combating compositions. It is a further object to provide pest-combating compositions containing pyrethrins in the presence of an economically attractive synergist therefor.

According to the present invention there is provided an improved pest combating composition comprising at least one pyrethrin and at least one aryl alkyl ketone.

Preferably the composition consists of a solution of pyrethrum extract and an aryl alkyl ketone in a hydrocarbon distillate fraction.

Suitably, the distillate fraction is a kerosene or white spirit fraction of petroleum.

Preferably the ketone is an aryl alkyl ketone in which the aryl group consists of an unsubstituted or alkyl substituted phenyl group.

Preferably, also, the ketone is an aryl alkyl ketone in which the alkyl group comprises 1-4 carbon atoms.

Particularly preferred ketones are acetophenone and the methyl acetophenones. Other ketones which may be employed include butyro phenone (propyl phenyl ketone) valero phenone (butyl phenyl ketone) and iso-capro phenone (iso amyl phenyl ketone).

In general it is found convenient to include in the pest combating compositions a proportion of a highly toxic insecticide to increase the percentage kill obtained by the insecticide. Suitable insecticides include the gamma isomer of benzene hexachloride, p,p dichlorodiphenyl trichloroethane and dieldrin.

Preferably the insecticidal compositions according to this invention contain 0.020.075% wt./vol. of total pyrethrins.

Preferably the ratio of aryl alkyl ketone/total pyrethrins is not greater than 15/ 1 wt./Wt. It is particularly preferred that the ratio lies in the range 5/1 to 15/1 wt./Wt.

Preferably the insecticidal composition contains up to 0.5% wt./vol. of a highly toxic insecticide, for example, benzene hexachloride.

By the use of compositions according to the present invention it is possible to obtain a satisfactorily short insect knock-d-own time, while effecting an economy in the use of the relatively expensive pyrethrum extract.

The invention is illustrated but in no way limited by the following examples.

The kerosene employed in the examples was a premium grade commercial petroleum kerosene fraction having the following characteristics Specific Gravity F./60 F. A. S. T. M. Distillation BP Cc 172 2% recovered C.

5% recovered 10% recovered 20% recovered 30% recovered 40% recovered 50% recovered 60% recovered recovered recovered recovered FBP Recovery Residue- Loss Recovery C. Recovery 200C" Recovery 240C..-

EXAMPLE 1 The essence of synergism is that pyrethrum plus synergist has a greater toxicity than either material alone, the toxicity of the mixture being greater than the sum of its parts. It has been found that if the synergist is sprayed before the Pyrethrum, the synergistic effect is just as strong and this is used to distinguish true synergism from pseudo synergism such as that exhibited by lubricating oils and oleic acid which have the physical effect of stabilizing the droplet size. To establish the true synergistic action of acetophone, the following tests were made in triplicate.

with 1 ml. of kerosene and eing sprayed with 1 ml. of the 10 (a) the volume of the chamber was 18.7 cu. ft. (i. e. approx. A of the vol. of the standard Feet-Grady chamber).

(b) the dosage used was man cases 1 ml. (i. e. A of the dosage employed in the standard method).

a spraying pressure of 10 lb./sq. in. was employed employing as the spray gun Aerograph Artists Brush with a No. 2 nozzle. 7

(d) the number of test insects employed was 90-104 per test.

Table 2 0.05% w./v. Pyrethrins with Acetophenone 0.1% 0.05% percent W./V. as below Insecticide W./V. w./v.

Pyrcth- Pyrethrlns rins 0.05% 0.15% 0.25% 0.40% 0.50% 0.60% 0.75% w./v. w./v. W./v. w./v. w./v. w./v. w./v.

. Aeetophenone I Rntw wn/w "I "I n, 1/1 3/1 /1 8/1 10/1 12/1 I 15/1 Time for 50% K. D. (seconds) 88 120 92 107 103 100 103 92 89 Time for 90% K. D. (seccuds) 153 241 231 191 160 159 154 144 190 Time for 100% K. D. (seconds) 373 538 360 445 433 420 400 360 300 Percent K. D. in 600 seconds. 100 100 100 100 100 100 100 100 100 Percent Kill in 24 hours 39. 2 13. 6 14. 7 12. 6 13. 0 14. 0 22. 4 22. G 23. 0

(c) The flies were sprayed with 1 ml. of kerosene and EXAMPLE 3 the same airing procedure adopted as in the tests under (a) and (b) before being sprayed with a blend of 0.05% w./v. pyrethrins plus 0.5% w./v. acetophenone.

The mean results of these three sets of tests are recorded in Table l.

the nine assays for each blend were The experiment described in Example 2 was repeated carrying out three assays 011 each of three different generations of Musca domestica L. The mean results of as shown in Table 3.

Table 3 0.1% 0.05% 0.05% \v./v. Pyrethrins with Acetophenone percent wt. as below Insecticide W./V. W./v.

Pyreth- Pyrethrins rins 0.125 0.025 0.05 0.15 0.25 0.35 0.40 0.50 0.60 0.75 1.0 Acctophcnone Y I RBtIO Pyrethrum w/w 0.25/1 05/1 1/1 t 3/1 5/1 7/1 8/1 10/1 12/1 15/1 20/1 Time for K. D. (8005.).... 82 133 106 110 114 100 101 82 90 101 101 103 90 Time or 90% K. D. (8005.) 149 276 259 275 253 268 179 174 177 173 173 201 230 Time for 100% K. D. (Secs.) 325 538 410 420 420 497 390 360 340 387 360 300 300 PercentILDJnGOO see0nds 100 100 100 100 100 100 100 100 100 100 100 100 100 Percent Ki1lin24 hours 44.7 13.4 13.0 13.1 14.7 17.0 17.3 18.3 18.3 17.3 19.8 10.0 22.0

Table 1 EXAMPLE 4 Method of Spraying Insecticide Method Method Method (a) (c) The elfect of adding chlorinated hydrocarbon contact *f insecticides to a Pyrethrum spray synergised with aceto- Time for 509 K. D. (Secs) 120 77 89 Time for K (SBCSLV J 218 140 140 phenone was studied by preparing, w1th kerosene as sol ITirne rot- 100 IQ DO. (secs r. 88 3 vent, three blends crcent .in O se-on 1 0 Percent 1311 in 24 hours 19.3 22.3 21.8 Contamlng O05% pyrethrins, 035% acetophone and 0.5 w./v. DDT (pp' dichlorodiphenyl trichloro ethane) I I (b) containing 0.05 w./v. pyrethrins 0.35% w./v. acctophenone and 0.1% w./v. pure B. H. C. (pure gamma isomer of benzene hexachloride).

(c) containing 0.05 w./v. pyrethrins 0.35% w./v. acetophenone and 0.1% w./v. dieldrin (hexachloroepoxy-octahydrodimethano naphthalene).

These blends were assayed in triplicate against a blend of 0.05 w./v. pyrethrins with 0.35 w./v. acetophenone using a 0.05 w./v. pyrethrins spray as control and the mean results of the tests are recorded in Table 4.

Table 4 0.05% w./v. Pyrethrins plus 0.05% w./v. 0.35% Ac ophenone With- 0.05% w./v. Pyrethrlns Insecticide Pyrethrins plus 0.35%

w./v.aceto- 0.5% 0.1% 0.1% phenone w. v. w./v. w.lv.

D T 3.11. C. Dieldrin Time for 50% K. D. 138 85 79 78 Time for 90% K. D. 277 135 135 157 234 Time for 100% K. 4, 455 260 358 570 570 Percent K. D. in 60 100 100 100 100 100 Percent K i 24 16. 7 19. 100 100 100 EXAMPLE 5 2. A compositlon as specified m cla1m 1 1n which the p-Methylacetophenone, propio-phenone and benzophenone were tested for synergistic activity by preparing three blends containing 0.05% w./v. pyrethrins with 0.35% w./v. of the appropriate compound under test in kerosene and assaying in triplicate each blend against a 0.05% w./v. pyrethrins blend. The mean results are recorded in Table 5.

We claim:

1. A pest-combating liquid composition comprising pyrethrin and phenyl alkyl ketone in which the alkyl group comprises 14 carbon atoms, the ratio of the total weight of phenyl alkyl ketone to total weight of the pyrethrin being in the range of from about 5:1 to about 15:1, said pyrethrin and phenyl alkyl ketone being in solution with a liquid hydrocarbon distillate fraction derived from petroleum.

fraction is a kerosene fraction of petroleum.

3. A composition as specified in claim 1 in which the fraction is a white spirit fraction of petroleum.

4. A composition as specified in claim 1 in which the ketone is acetophenone.

5. A composition as specified in claim 1, and having included therein, the gamma isomer of benzene hexachloride.

6. A composition as specified in claim 1, and having included therein, pp dichlorodiphenyl trichloro ethane.

7. A composition as specified in claim 1, and having included therein, dieldrin.

8. A composition as specified in claim 1 in which the total amount of pyrethrins present is 0.02-0.075 wt./vo1.

9. A pest-combating liquid composition comprising 0.02-0.07 5% wt./vol. of pyrethrin; acetophenone, the ratio of the weight of acetophenone to the total weight of pyrethrin lying in the range of from about 5:1 to about 15: 1; a pesticide selected from the group consisting of the gamma isomer of benzene hexachloride, p,p'-dich1orodiphenyl trichloro-ethane, and dieldrin, the foregoing being in solution with a liquid hydrocarbon distillate fraction derived from petroleum.

References Cited in the file of this patent FOREIGN PATENTS 494,463 Germany Mar. 24, 1930 350,897 Great Britain June 15, 1931 126,959 Australia Feb. 25, 1948 OTHER REFERENCES J. Econ. Entomology, vol. 44, December 1951, p. 896. 

1. A PEST-COMBATING LIQUID COMPOSITIO COMPRISING PYRETHRIN AND PHENYL ALKYL KETONE IN WHICH THE ALKYL GROUP COMPRISES 1-4 CARBON ATOMS, THE RATIO OF THE TOTAL WEIGHT OF PHENYL ALKYL KETONE TO TOTAL WEIGHT OF THE PYRETHRIN BEING IN THE RANGE OF FROM ABOUT 5:1 TO ABOUT 15:1, SAID PYRETHRIN AND PHENYL ALKYL KETONE BEING IN SOLUTION WITH A LIQUID HYDROCARBON DISTILLATE FRACTION DERIVED FROM PETROLEUM. 